The phosphor Y.sub.3 Al.sub.5 O.sub.12 :Tb exhibits green emission under electron excitation and is used in special CRT applications as heads up displays and projection TV systems. The phosphor is useful in that it exhibits linear burn resistance, more linear than Y.sub.3 (Al,Ga).sub.5 O.sub.12 :Tb and thus is utilized under high beam current densities. The phosphor is not as efficient in luminescence output as Y.sub.3 (Al,Ga).sub.5 O.sub.12 :Tb, therefore is not significantly utilized in these applications.
A method by which Y.sub.3 Al.sub.5 O.sub.12 :Tb can be made more efficient would be desirable.
U.S. Pat. No. 4,479,886 relates to making Y.sub.3 Al.sub.5 O.sub.12 :Ce phosphor in which barium fluoride is added to the finished phosphor to increase the efficiency of converting UV radiation to visible radiation.
U.S. Pat. Nos. 4,070,301 and 4,141,855 disclose the addition of a barium compound to a cerium activated phosphor prepared from yttria and alumina to enhance the intensity of UV emission of the YAlO.sub.3 :Ce.
A publication entitled "Effect of BaF.sub.2 on the Synthesis of the Single Phase Cubic Y.sub.3 Al.sub.5 O.sub.12 :Tb", by K. Ohne and T. Abe, J. Electrochem. Soc., Vol. 133, No. 3 (March 1986) discusses a high concentration of BaF.sub.2 (20%) on Y.sub.3 Al.sub.5 O.sub.12 :Tb phosphor but does not consider particle size.